Insulation for laser connections

Questions, Suggestions, Tips, Etc

Insulation for laser connections

Postby dwjp » Sat Dec 08, 2012 7:00 am

This is part warning to others, part query...

My 2.x laser is almost complete, and I've been doing some test jobs to try things out. While cutting a piece of paper, I noticed some buzzing, and that the laser power was fluctuating. A moment later the positive connection to the tube was in flames and had popped off. I hit the emergency stop, and put it out with the fire extinguisher. Massive overkill (the flame was match sized), but I didn't want to get too close.

I think the problem was the self-amalgamating butyl rubber tape I used to cover the connections (from http://www.jaycar.com.au/productView.asp?ID=NM2826). While it is supposed to be for high voltages, and able to resist coronas, I found later that it's very easy to set alight! I had assumed that given the intended application it would include some flame retardant additives.

I'm going to try some silicone rescue tape instead, can anyone give suggestions on a particular brand fit for the application, or is the generic rescue tape good enough? Any extra tips on getting a secure, non-flammable connection (using a potting compound for instance to completely exclude air)?
dwjp
 
Posts: 29
Joined: Mon May 31, 2010 7:41 am

Re: Insulation for laser connections

Postby BenJackson » Sun Dec 09, 2012 1:27 am

I'm pretty sure this is in the 2.x instructions.

First I stripped the positive and negative supply wires back 2x the length of the stud on the laser.

Holding the stripped end parallel to the stud and flush with the end (extending past the tube, in the opposite direction of the final connection), I used a very fine tinned wire (one strand from a stripped stranded wire) wrapped around and around the stud and the supply wire. This makes a very tight connection.

Now you can bend the supply wire back the other way so it sticks out in the desired direction. I used a long piece of self-fusing silicone tape to go around the tube and cover the stud on both sides. Then I wrapped another piece around the stud to reinforce it.
BenJackson
 
Posts: 522
Joined: Fri Apr 15, 2011 6:13 pm

Re: Insulation for laser connections

Postby dwjp » Sun Dec 09, 2012 2:22 am

Yes, that's pretty much exactly what I did, except I used self-amalgamating butyl rubber tape instead of silicone, which I presumed would be equally suited to high-voltage connections, however it has caused me trouble.
dwjp
 
Posts: 29
Joined: Mon May 31, 2010 7:41 am

Re: Insulation for laser connections

Postby jv4779 » Sun Dec 09, 2012 6:35 am

I used http://www.harborfreight.com/1-x-10-ft-self-bonding-super-tape-68401.html on mine and it has not shown any issue for a 8 months. The wire is connected to the laser tube wire stud with the metal part of http://www.radioshack.com/product/index.jsp?productId=2103986 removed from the plastic. You end up with a little metal tube with two set screws.
jv4779
 
Posts: 40
Joined: Fri Dec 09, 2011 10:54 pm

Re: Insulation for laser connections

Postby TLHarrell » Sun Dec 09, 2012 6:59 pm

I used clear household silicone caulk and a short piece of silicone tubing to pot and reinforce the connections.
40w Full Spectrum Engineering 5th Gen Hobby 20"x12" w/ Rotary Engraver
South San Francisco Bay Area - Sales and Support Representative for Full Spectrum Engineering
408-47-LASER - Skype: whitelightlaser-thomas - Facebook: White Light Laser
TLHarrell
 
Posts: 419
Joined: Thu Jul 28, 2011 11:30 pm
Location: Morgan Hill, CA

Re: Insulation for laser connections

Postby canadianavenger » Mon Dec 10, 2012 1:06 am

TLHarrell wrote:I used clear household silicone caulk and a short piece of silicone tubing to pot and reinforce the connections.


I would recommend against that. Silicone caulk contains acetic acid, that will corrode your connections over time.
canadianavenger
 
Posts: 153
Joined: Wed Nov 30, 2011 3:24 am

Re: Insulation for laser connections

Postby cvoinescu » Mon Dec 10, 2012 12:00 pm

There is neutral-cure silicone caulk too. The household version is sold for use on acid-sensitive stone (e.g. travertine, marble).
cvoinescu
 
Posts: 501
Joined: Thu Aug 09, 2012 9:12 am
Location: Camberley, Surrey, UK

Re: Insulation for laser connections

Postby Speedythinker » Mon Dec 10, 2012 11:04 pm

Speedythinker
 
Posts: 135
Joined: Wed Oct 19, 2011 12:06 am


Return to 2.x Laser Support

Who is online

Users browsing this forum: No registered users and 11 guests

cron